This invention is particularly applicable, though not exclusively so, to electronic control systems for single-cylinder-engined motorcycles. Forthcoming legislation relating to permitted exhaust emission levels for these vehicles is driving a transition from discrete ignition and carburetor designs towards microcontroller-based ignition and fuel injection. This increased use of electronics brings with it complexity, including the complexity of calibration, which for fuel injection is several hundred parameters as opposed to a handful of mechanical parts on a carburetor. In addition, expensive calibration equipment, which in many cases can only be operated by trained personnel, is required. Thus it would be advantageous to provide a simple electronic solution whereby calibration could be performed using a laptop computer and without requiring software skills.
Some vehicle manufacturers integrate a diagnostics communication link into their electronic engine control units. This new complexity is often beyond the capabilities of a local repair shop, but a typical engine control unit can be programmed to diagnose both itself and the vehicle's on-board sensors and actuators which are connected to it and thereby report faults to the repairer
Certain emissions standards also require fault reporting by way of a vehicle-mounted malfunction indicator lamp.
Thus the manufacturing industry for about 40 million motorcycles worldwide needs to update their engine controls over the next five to ten years to include a microcontroller, calibration, diagnostics interface, and fault lamp.
The Freescale 33813 engine control unit, described in Freescale Document number MC33813 Rev. 1.0, 8/2012, provides a tachometer drive output pin, a lamp drive output pin and a bidirectional line output for providing diagnostic support to an associated microcontroller. Each of these three functions requires a separate pin and separate driver, however, thus adding complexity and cost to the components required for engine management compared with pre-legislation designs.